The chairman of the Senate Intelligence Committee says 60 percent of the al-Qaida leadership is in custody. Senator Pat Roberts says international cooperation in combating terrorism is on the rise.

Senator Roberts said progress is being made in reining in al-Qaida. The Republican from Kansas said the recent arrest of the man believed to be the group's main operative in Southeast Asia was a real blow to the terrorist network. "There will be others that will try to take his place. But when you take the operations chief out of the picture, it does pose a lot of problems," he said.

President Bush personally announced the arrest of the man, known as Hambali, the suspected leader of a southeast Asian terrorist group called Jemaah Islamiyah. Mr. Bush called him one of the world's most lethal terrorists, and noted he is believed to be the mastermind behind last year's bombing in Bali, Indonesia.

There have been reports the terror suspect was planning an attack on the Asian-Pacific summit scheduled for October in Bangkok, Thailand. Speaking on CNN's Late Edition, Senator Roberts said he could not confirm the reports, but indicated he would not be surprised if they prove to be true. "I can not tell you anything specific about it," he said. "We will probably have another briefing on it. We have threat warnings or threat briefings every week in the Intelligence Committee. But that part of the world was beset by these problems. That is why this arrest and this capture are so [very] important."

Mr. Roberts said the arrest also shows that more countries are realizing the importance of co-operating with the war on terrorism. He was then asked about the level of help coming from Saudi Arabia. "I think it is much better. After the Riyadh attack, which was their own 9-11 attack, we have much better cooperation on the intelligence side. They have arrested over 200 people at severe loss of life to their security forces," he said.

Senator Roberts described the Riyadh attack in May as a wake-up call for Saudi Arabia. Appearing on the same television news program, the Saudi government's chief foreign policy advisor, Adel al-Jubeir, called it a massive jolt to the country. "When normal people leading normal lives get murdered in our midst, we are shocked into action," he said.

Mr. al-Jubeir said the recent decision by British Airways to suspend flights to Saudi Arabia was based on information obtained by the Saudis in the course of interrogating terror suspects. He said the flight suspension may have been a bit of an overreaction, but quickly added it was a decision for Britain to make, based on the evidence at hand.